Viscosity pump for cooling face seals



Feb. 21, 1967 F. T. STAHL VISCOSITY PUMP FOR COOLING FACE SEALS 3 Sheets-Sheet 1 Filed May 7, 1965 Feb. 21, 1967 F. T. STAHL VISCOSITY PUMP FOR COOLING FACE SEALS Filed May 7, 1965 3 Sheets-Sheet 2 k h A Feb. 21, 1967 RT. STAHL 3,304,876

led May 7, 1965 3 Sheets-Sheet 5 United States Patent 3,304,876 "ISCGSITY PUMP FOR COOLING FACE SEALS Filip Torvald Stahl, Alvsjo, Sweden, assignor to Alitiebolaget Flygts Pumpar, Solna, Sweden Filed May 7, 1965, Ser. No. 454,030 Claims priority, application Sweden, May 15, 1964, 6,002/ 64 3 Claims. (Cl. 10387) The present invention relates to a viscosity pump for cooling face seals in a centrifugal pump unit, particularly in units for pumping out water which has collected during excavating and blasting work. Consequently it concerns a unit of the so called submersible type, that is to say a unit which can be completely submerged in water and which consists of a pump housing having a vertical shaft and a motor unit built together with said pump housing. In order to prevent the pumped fluid in such a pump unit, from penetrating into the motor chamber, an oil chamber is arranged between the bottom of the motor chamber and the upper restricting wall of the pump housing, and through which oil chamber is passed the vertical shaft of the unit, whereby said chamber by means of seals, is restricted firstly towards the motor chamber and secondly towards the pump housing. The seals are constructed thereby as sealing cartridges with face seals,

- which are pressed against an opposite sealing surface with the assistance of a spring actuated rubber cuff. The face seals are intended to rotate together with the shaft of the unit and remain thereby under a certain over pressure exerted by the oil existing in the spring loaded cuffs, whereby a certain lubrication of the face seals is always ensured while at the same time the penetration of condensation possibly existing in the outer chamber or fluid from the pump chamber is prevented by the upper and lower seals, respectively. So that sealing in the positions in question will be adequate, face seals in questions are subjected to relatively high sealing pressures and consequently become very hot, even if in certain constructions attempts are made, with the help of radial holes in a slip ring between both the face sealing rings, to pump oil into the interior of the above mentioned rubber cuffs and/or through the slip ring. Temperatures of over 135 C. for the face seals in question are not unusual.

The present invention intends to avoid the said inconveniences by arranging that the oil is pumped to the face seals more effectively through the slip ring with the assistance of a viscosity pump, and comprises mainly in that the slip ring, retained in the oil chamber by means of a slip ring holder, is supplied with at least one channel, e.g. parallel to the plane of the slip ring, in communication with the oil chamber, for attaining a better oil flow and thereby a better cooling of the sealing rings and the slip ring; and that the shaft of the unit and a bushing or the like which rotates with the shaft and which is arranged upon said shaft respectively, is thereby used as a rotor in the thus formed viscosity pump in which the slip ring serves as a wiper. According to a specific embodiment of the invention said channel is tangential to the shaft of the unit and the bushing or the like arranged on said shaft and rotating with the same.

According to one embodiment of the invention the slip ring, which is provided with a sealing ring arranged on its upper and lower surface at the peripery, is thereby constructed with double channels tangential to the shaft of the unit and the bushing or the like arranged thereon respectively, said bushing rotating with the shaft, whereby the inner periphery surface of the slip ring between the channels thus serves as two wipers.

According to a second embodiment of the invention the slip ring is provided with a recess or groove arranged 3,3fl4,876 Patented Feb. 21, 1967 around its circumference, so that a recirculation chamber around the ring is formed. Due to the viscosity pump according to the invention, an increased oil circulation is produced around the shaft as well as a larger delivery of oil to the sealing rings whereby these are cooled more effectively. With a centrifugal pump unit provided with a viscosity pump according to the invention, tests have shown a reduction of the temperature of the face seals of from 2530 C. down to around C.

Due to the invention a simplification of the manufacture of the slip ring has been gained in so far as that only one or two drill holes tangential to the shaft of the unit are needed instead of the previously used six radial drill holes.

An embodiment of the invention will now be further described in connection with the attached drawings, on which FIG. 1 shows, in a cut away View, a lower section of the centrifugal pump unit with the viscosity pump according to the invention,

FIG. 2 shows a perspective view, partly cut away, of a section of the oil chamber with the shaft of the unit passing through the same and also its face seals, and

FIG. 3 shows a detailed view also in perspective, of a viscosity pump according to the present invention.

In the lower section of a centrifugal pump unit shown in FIG. 1 a vertical shaft is indicated by the reference numeral 1, a motor stator housing 2, an outer cooling jacket, arranged in the shown embodiment for the motor unit by 3, an impeller by 4, the bottom section of the pump housing by 5 and its upper section by 6. The pump housing is conceived as being internally coated with a rubber protective lining, which is indicated by the reference numeral 7 at the lower section of the pump housing and on the upper section of the pump housing by the reference numeral 8. A frame 9 of the pump is arranged in connection to the outer cooling jacket 3, which frame is constructed in the form .of a sieve. The impeller 4 is secured on the nick 12 of the motor shaft by means of two nuts 10 and 11. On the upper section 6 of the pump housing a slip ring holder 13 is arranged which connects to the bottom 14 of the motor housing and which at the bottom forms a chamber 14a surrounding the shaft and which partially closes the pump housing, into which chamber 14a fluid from the pump housing penetrates. In said chamber, the lower seal of the shaft is arranged against the pump housing and said chamber is sealed at the top by a slip ring 15, carried by the slip ring holder, with the assistance of a sealing ring 16. An annular chamber between the upper section 6 of the pump housing and the bottom 14 of the motor chamber is indicated on the drawing by the reference numeral 17 and is filled with oil. Thus chamber communicates with the interior of the slip ring through a substantially annular groove 18 in the slip ring holder and channels 19 and 20 extending tangentially towards the shaft. The upper section 21 of the bottom of the motor housing is shaped as holder for a ball bearing 22, an upper face seal being arranged between said ball bearing and the slip ring 15. A cuff 23 is arranged above the ball bearing 22, which cuff can be filled with consistent grease or the like.

At the bottom of FIG. 1 the water pressure on the impeller has been indicated by a pressure curve P. The pressure is thereby naturally highest at the outer periphery of the impeller and decreases in towards the center of the impeller. The pressure difference triangle P between the pressure at the periphery of the impeller and the pressure at that position on the impeller approximately opposite the periphery of the suction openings is thereby the pressure difference, which in the shown construction exists between the inside of a lower face seal and the chamber 14a surrounding said face seal. This proportion is produced through the following construction:

In the upper section 6 of the pump housing and its rubber coating 8, an opening 24 is arranged approximately at the same distance from the center shaft at the periphery of the suction openings. A bellow type annular rubber diaphragm 25 is arranged above the upper section 6 of the pump housing, which diaphragm, despite said opening 24, closes the oil chamber 17 opposite the liquid of the pump housing. The rubber diaphragm is securely inserted at its outer circumference into the bottom ection 14 of the motor chamber by means of a thickened annular edge, and at its inner circumference by means of a downwardly bent cuff and a bead securely clamped against the slip ring holder 13 by means of an elastic coil or elastic cord 25a. Pressure through the opening 24 in question thus propagates to the oil chamber 17 and therefrom via the tangential channels 19 and 20 to the inside of the face seals around the shaft of the unit and thus also to the lower face seal where said pressure thus acts so that a certain small amount of oil can seep out through the face seal into the chamber 14a and thus prevents water from entering.

The viscosity pump and the rubber cuffs of the face seals are somewhat more specifically illustrated in the perspective diagram according to FIG. 2. Corresponding sections in FIG. 1 and FIG. 2 have been given the same reference numerals. As can be seen from FIG. 2 the slip ring 15 arranged in the slip ring holder 13 is scaled downwards towards the chamber 14a by means of a sealing ring 16 and upwards towards an inner chamber 26 in the bottom section 14 of the motor chamber by means of a sealing ring 20. Said chamber 26 communicates by means of a hole 27 with the interior of the motor chamber. A face sealing ring 31 rests downwardly and upwardly against the slip ring 15 and under the action of a spring 29 in a rubber cuff 30 operating as an elastic carrier, which sealing ring 31 on its inside forms a chamber 32 communicating with the tangential channels 19 and 20, so that oil is also found in said chamber 32, which oil is under a certain overpressure thus preventing water from penetrating the interior of the sealing arrangement. The rubber cuff 30 in turn presses on to a lower interjacent washer 33 which lies against a shoulder on the shaft 1. The inner ring of the ball bearing 22 is also seated on the same shoulder.

A sealing ring 34 similar to face sealing ring 31 rests on the upper side of the slip ring, which face sealing ring 34 is carried by a rubber cuff 35 of the same type as rubber cuff 30, in the inside of which is arranged a spring 36 similar to the aforementioned spring 29. The rubber cuff 35 is also pressed against an upper washer 37 which lies against a shoulder on the shaft 1. The thus formed two face sealing rings, the upper comprising sections 34, 35, 36 and 37 and also 15, and the lower comprising sections 31, 30, 29 and 33 and also 15 are each carried by bushings 38 and 39 respectively arranged on the shaft 1. The bushings 38 and 39 in turn are supported due to the fact that the nuts and 11 exert a pressure directed upwardly against the impeller 4. The pressure is propogated through the intermediate washer 33 and the rubber cuffs 30 to said bushings 38 and 39 and also the rubber cuff 35 and the washer 37 which lies against a shoulder on the shaft 1 against which the inner ring of the ball "bearing 22 is seated. The upper face sealing ring 34 closes, similar to the lower sealing ring, a chamber 40 filled with oil. Oil is thus caused to flow around both the bushings upon rotation of the shaft and the viscosity pump operating through the tangential channels 19 and 20, which oil flow effectively cools both the face sealing rings 31 and 34 and also the slip ring 15.

The construction of the viscosity pump is further illustrated in a somewhat enlarged scale in FIG. 3, whereby a portion of the shaft of the unit 1 is shown, similarly a portion of the upper bushing 38. Similarly both the tengential channels 19 and 20 and the slip ring holder 13, are shown at the same time as a cut away section of the slip ring 15 is illustrated. The lower face sealing ring 31 is shown at the bottom of the drawing.

Although the invention is described in connection with an embodiment of the same, it can, however, be varied in an arbitrary manner within the scope of the following claims.

What I claim is:

1. A viscosity pump for cooling face seals in centrifugal pump units, particularly those of a submersible nature comprising a drive shaft adapted to be interconnected between a drive motor and a pump impeller, slip ring holder means disposed about and spaced from said shaft, housing means connected to said holder to define a lubricant containing chamber, annular slip ring means supported by said holder and disposed in spaced concentric relation to said shaft, sealing means disposed on opposite sides of said slip ring in sealing relation to said shaft and said slip ring and channel means extending through said slip ring tangentially to said shaft and in fluid communication with said chamber and said shaft whereby said shaft and said slip ring provide a viscosity pump for upplying lubricant under pressure from said chamber to said sealing means.

2. A viscosity pump as set forth in claim 1 wherein said annular slip ring means is provided with two parallel channels extending entirely through said slip ring and intersecting the central shaft receiving bore adjacent opposite sides of said bore whereby the inner periphery surface of the slip ring between the channels will serve as two wipers.

3. A viscosity pump as set forth in claim 1 wherein said slip ring holder is provided with a plurality of recesses adjacent the outer periphery of said annular slip ring means whereby said channel means may communicate with said chamber.

References Cited by the Examiner UNITED STATES PATENTS 2,223,519 12/1940 Hornschuch 27722 ROBERT M. WALKER, Primary Examiner. 

1. A VISCOSITY PUMP FOR COOLING FACE SEALS IN CENTRIFUGAL PUMP UNITS, PARTICULARLY THOSE OF A SUBMERSIBLE NATURE COMPRISING A DRIVE SHAFT ADAPTED TO BE INTERCONNECTED BETWEEN A DRIVE MOTOR AND A PUMP IMPELLER, SLIP RING HOLDER MEANS DISPOSED ABOUT AND SPACED FROM SAID SHAFT, HOUSING MEANS CONNECTED TO SAID HOLDER TO DEFINE A LUBRICANT CONTAINING CHAMBER, ANNULAR SLIP RING MEANS SUPPORTED BY SAID HOLDER AND DISPOSED IN SPACED CONCENTRIC RELATION TO SAID SHAFT, SEALING MEANS DISPOSED ON OPPOSITE SIDES OF SAID SLIP RING IN SEALING RELATION TO SAID SHAFT AND 